Remote control system



Oct. 19, 1943- G w. BAUGHMAN ETAL REMOTE CONTROL SYSTEM Filed July 5, 1941 m UHU .NM w www@ w www QNQANM .BMU

Patented Oct. 19, 1943 anMorncoNraoL SYSTEM George W. Bllghmn,

' Ag-new, Penn Town wla., Yassignors to The :Un

Wissvale, Pa., a corporation of Penn- Company, S Sylvania Swissvale,I and Norman lapplnation'il'li'ly 51 194 1i ola-img. (ci. iwf-353) Our vinvention relates `vtov remote control SYS- tems, and more particularly to centralized traffic control systems for Yrailroads.and to v,thefline .circuits employedby sucio. systemfS,. l v f It is lusually the `case thata' fdispatchers telephone yline equipped withicalr'selectors extends 'throughout the 'lengthofgany railroad territory Whichjisto be controlled 'by a 'centralized' traic control system', andmarked economy may be effected by the use )of :thesame'jline` Wires jointly by the telephones, the dispatcheriscall selectors and the centralizedtraic .control system. Our invention relates to; improved VarrangementsA by which this may be Vaccompiished and is an Vimprovement upon that disclosed lin aprior application, Serial 110,261,241, filed 'MarchlL V41939, for Remote control systems, by `Lloyd V. Lewis, now Patent No. 2,259,573, issued October'Zl, 1941, and upon that disclosed in our prior application Se-l rial No. 326,44),led March-28,1910, forRernote control systems, now 'PatentjNo 2,303,815, issued December 1, 1942. The "systems of both ythese applications are ofthe impulse code type, andas illustrated', employfcoding apparatus of thejty'pe shown in the Lewis/Patent No: 2,229,249, 4granted January A21, 1941. In 'the vsystem of. Seriallflo. 261,241, the coding'fapparatnsis adapted to oper; ate over anorrnally 'openbridgedjline circuitwith each station, while that-of Serial,No'.r 325,114ilfem-v ploys a normally clcsed line cireuit'with a source of linef'current-at thecontrol office only. `In both of :theseA systems there' are codetransmittersat the-C. T. C stati-ons at .spaced points along the trackas Well as one `atthec'orrtrol omcaand in additionthereis also a transmitter at the oiiice for 'transmitting 'teieplione callselector codes over the `same line, circ uit. L `All-of jthese transr` -mittersy have accessjtot'ne 'line 'circuitl but ,only when :it is Tree, and -theinitlatonf cia codeby anyone -loeksout all theA others,4 thegarranvg'ement .local 'sources-'of line energy attheofceandat ship, .Allegheny County,

ion Switch & Signal l, SeriallNo. 401,092

.ccclewheel When the'lne is in useby the"`C.'T. C. system and the;selector transmitter consequently does notghaye accessjto 'the line.

"The system` disclosed herein functionsk in a somewhat similar mannen vbut in accordance Withjthe presentgfinventionno such restr iction upon .the reiease of ka code Wheel is necessarmjand the operator of the call selector systemmaysgain yaccess to the line at any time Wholly Without regard'to Whether or not it is `then in .Lise by "the C. T. C. system. The release of the code Wheel temporarily disconnects `the source 'of Vthe 6;'1. C. 'signals from the line, thereby freeing -the line yand preventing any `interi'terence1` with thefselector code by the C. T. fsystem. 'if it happens that Ya` code Wheel isreleased during the transmission of ra C. T. "C. codefthe :flatter of course isinterruptedbut each CNI. C. transmitter vis'provid'ed with larrangements vfor storing a codelinterrupted at any step of its transmissions@ that such code will be retra-nsrntt'ed from the beginning as soon as the line becomes free. .4 In. accordance-With a feature ofour invention, the` arrangements for 'interrupting the operation of the C. systernare adapted to be controlled from" -a remote point, and'this may beeii-ected, for example, over a distinctive frequencyjchannel employing thesame line Wires" but-without interference either with ther transmissionof -vVoice .frequencies -or of selector codes, *withtliepadvana "tage Ythat-fine C. T. C. vsyster'n,may be controlled n from any desiredv point on 'the line 'Wthoot refio beingsuch that if tvro'or,` more initiate'tlieir vcodes at the lsaine-time the codes are "transmitted one at a time in order without interference. 'Fu'rthermore, these system'sembloymanuaily Areleasable code wheels for sending selector codesjas in the Field PatentlNo. '1;313,256,-of June'- 15, 1920, but over the same line -Wiresas used 4for transmission :of .C. ET. codes. *Since devices of that kindmustsend their codes immediately when released,.or not at all, thesystems-are so arranged that ithe selector codes' havejpriority over T.'"C codes in the" event jtwo o'r' lmore codes are initiated atetliesame time; anda vguard. lamp' is provided V:t'o' Warnthe selector opera-tor against releasing a its `gard to the location of the selector transmitter. Tlielatter is usually located ina train -'iise patchers -o-ffce which, may, 'for example, 4be at a division headoluartersk a considerable vdistance from any-point in the-'territorycontrolled cy-the CfrCfsySem ,s f Our inyention is particularly'advantageousfor useA withv C: T. systems 'of th'eicentral/ loat-v tery typey having asingle vsource of linecurrent locatedI at fthe C. .'I Ci office,l either. of 'the bridged 1 lijn@ "circuit time 'as Shown in four priori applica tion,' or of, the series'ftlypef' as in atent No. 2,229,249, for the reaspnrthai 4by interrupting 'the suply of 'current .to fthe line at its soiir'c, the

operation of the C.' T.4 C; systemrmaybe'temy plm-amy suspended whenever ,thisis required, in a very' simple manner', Withoutregard ,to the location `of the transmitter "in operation. at the time." v v One form of our invention, and .several v'modiiications thereof will now' be described, and the 'noveiafefatures ther-eoflwiu men ,ce Vporra-.ed .cui

in claims.'

Referring to the accompanying drawing, Fig. 1 illustrates diagrammaticaily one forni of our invention, Fig. 2 shows the internal circuits for an amplier suitableJ for use as the device A in Fig. 1, while Fig. 3 illustrates mocliiication of the circuits for the transformer 20 of Fig. l.

Similar reference characters refer to similar parts in each of the views, l

Referring to the drawing, the reference characters Y and Z designate the two line wires extending along the track which provide a normally closed line circuit for the transmission of impulse codes in either direction Abetween-the Aoffice and stations of the C. T. C. system. This is shown as a series circuit, as in Fig. of Patent 2,229,249, but modified to permit voice communication over the same line wires in the manner pointed out in the Baughman Patent No. 2,208,446, issued July 16, 1940, and to also include a back contact of a normally deenergized relayI F' at the C. T. C. office. For simplicity but one C. T. C. eld station is shown, but' it will be understood that in general the C. T. C. system will include a plurality of such stations each arranged like the one shown.

To facilitate an understonding of our invention, we have designated those relays shown herein which function like corresponding relays of Patent No. 2,229,249, by reference characters similar to those of the patent, and it is to be understood that all of the C. T. C. apparatus, the operation of which is not specically described herein, functions in the' manner described in this patent. The circuits for certain of these relays are vreproduced herein lnerely for convenience although identical with corresponding circuits of the pat# ent, while the circuits for othersv are modified, as will be pointed out hereinafter. v

As shown herein, the C. T. C. line circuit is normally closed and extends from the central battery 80 at the C. T. C. omce over back contacts of relay F and of the oice transmitter relay OT through the windings ofthe oice line relayr OR and of a low pass filter 8 to the line wires Y and Z, and thencethrough ea'ch C. T. C. station in turn, passing through the windings of the line relay R and over back contacts of the master relay M at each station, the line circuit being completed by a low resistance reactive connection between line wires Y and rZ,Hwhich in the i' particular arrangement shown comprisesthe secondary of a transformer at the train dispatchers oice. It will v'be clear that none of.

these modifications of the line circuit change the normal mode of operation of the system of Patent No. 2,229,249 in any way, and that as long as relay F is in its released position, C. T. C. control codes may be transmitted by the operation Vof relay OT, and indication `codes may be transmitted by the operation of relay T at any C. T. C. station, precisely as described in this patent.

The line wires Y and Z also provide a telephone channel suitable for train dispatching or message transmission, extending between the terminal telephones 9 lat the opposite ends of the line as shown, or from the dispatchers office to any one of a'plurality of intermediate points such as the one designated selector station on the drawing, atwhich a telephone may be connected to the line through a jack 11, to answer aV call resulting from the operation of an associated telephone call selector 12.

It is to be understood that the selector station shown is but one of a plurality of similar stations having access to line wires Y and Z, and

- ,operated code wheel, there being a different code wheel for each selector 12. The reference characters for these parts are the same as those of corresponding parts shown in Patent No. 1,343,256 hereinbeforereferred to, and their detailed mode of operation may be ascertained from this patent.

The transformer 20 is interposed between the selector transmitter and the line wires to isolate the two line batteries 80 and 85, and to prevent current from battery 85 from passing through the selectoi1 windings, serving the same purpose as condensers 14 loi" Patent No. `1,343,256 in permitting the selector to assume a neutral position during the pauses in a selector code, and these condensers are accordingly omitted.

Relay F, at the C. T. C. office, is a repeater of relay 86 atthe dispatchersl olce, andit disconnects battery 80 from the line whenever a selector code is being transmitted, When these offices are located at diierent points on the line, as shown, relay F is controlled over a non-inten tering line channel including the line wires Y and Z by means of alternating current of a particular frequency, preferably of low value and outside the voice frequency range.

As already mentioned, the operatorat the disc patchers office may release a code wheel at any time, regardless of whether or not a C. T. C. code is being transmitted. As soon as the code wheel rotation starts a circuit is completed from one terminal B of a local source of current over contact springr 96 to wheel 89 and thence through relay 8S to the other terminal C of the local source. As shown in the drawing, the code wheel teeth are so disposed that relayv 86 picks up before the transmission of the selector code by relay 81 begins, and releases just after it is completed. A transformer having its primary connected to terminals BX and CX of a suitable Source of alternating current has its secondary connected through a tuned circuit including coil 3| and condenser 32, the'contacts of relay 86 and the windings of transformer 20, across line wires Y and Z, so that alternating current is delivered to the line as long as relay 86 is picked up. This current passes through relay R and the back contacts of relayM at each intervening C.,'T, C. station (or through the by-pass condenser l l if relay M isy picked up) to the C. T. C. cfce, where it is effective to pick up relay F by reason of a connection to WiresY and Z including an amplifier A, and a tuned Iilter circuit comprising the transformer 33, coil 34 and condensers 35 and 36, as shown.

Relay F, when picked up, opens the C. T. C. line circuit by disconnecting ybattery 88 from the line,rwhich suspends the operation of the C. T. C. system lfor the duration of the selector code, and at the same time conditions ,the line circuit as required for the proper 4operation of the selectors 12, since these have windings of relatively high resistance bridged across-the line and otherwise would be shunted by the low resistance connection between-Wires Y and Z through battery 80. 'It is clear therefore that the C. T. C. system in transformer, 33, and is non-responsive to impulse excita-tion due to thecodes or to. switching, and .is also non-responsive to the voice frequency currents. l

Although we have herein shown and'described but one form ofapparatus embodying our invention, and i several modiiicaticns thereof, it is understood that various changes and modifications may be made thereinl Within the scope vof the appended claims Without departing from the spirit and scope of our invention.

Having thus described our invention, what we claim is:

l. In combination, an oice and a station connected by a line circuit, a remote-control system having a plurality vof code transmitters including one at said oiiice and one at said station each having'a transmitting contact, means, for initiating the operation of each code transmitter effective only when the line is free, means controlled by each code transmitter When initiated for operating its transmitting contact repeatedly to deliver an impulse code to said line circuit, a starting relay for each transmitter free to be actuated at any time for controlling the initiation of Vthat transmitter, holding means for each starting relay eiiective -to maintain it lactuated only until one complete code initiatedthereby is transmitted byv the uninterrupted repeated operation of the associatedtransmitting contact,

an additional code transmitter having access at times tosaidline circuit, meansoperable irrespective of Whether or not the line circuit is in use for initiating the operation of said additional code transmitter to deliver other impulse codes to said line circuit, and meansrendered eiiective when said additional transmitter is initiated for immediately interrupting the operation oi 'the transmitting contact of any remote control system transmitter then in operation while retaining the starting relay associated therewith in its actuated condition and eifective to initiate the transmission oi a code in its entirety as soon the code delivered by said additional transmit-ter is fully transmitted. l

2. In combination with a line circuit, a remote control system transmitter having access to said line circuit to deliver an impulse code thereto, a starting relay free to be actuated at any time for initiating the means preventing the initiation of said transmitter in response to the actuation of said starting relay except when the line is free, holding means for each starting relay eiective to maintain it actuated only until one complete code initiatedY thereby is transmitted, an additional transmitter having access at times to said line circuit, means operable irrespective of .Whether or not. Said line circuit is in use for initiating the operation of said additional transmitter to deliver a different impulse code to said line circuit, and means rendered effective when said additional transmitter is initiated for immediately interrupting the operation of said remote control system transmitter if such transmitter is then in operation and for reinitiating the operation of the interrupted transmitter to transmit its code in its entirety as soon as the code delivered by said additional transmitter is fully transmitted. u

3. In combination, anv office and a station connected by a line circuit, a remote control system having a plurality of code transmitters including one at said omce and one .at said station each operable when the line is free, to deliver an imoperation of said transmitter,

pulsecode comprising a predetermined number ofi impulses each of 'determinable character to said line circuit, Va manually releasable code Wheel operable when releasedto deliver a different impulse ,code toisaid line circuit, interference preventing means responsive to the release of said code wheel and eiective when a code is being Vtransmitted by said ofce .or station transmitter for stopping theoperation thereof, thereby interrupting said` code immediately upon the release ofsaid code Wheel, storing means associated with the.. transmitters of said remote control system for storing each such interrupted code for transmission in its entirety when. the line becomes free, and means .controlledA by said interference preventing means for reinitiating .the transmission of said stored code inits entirety after the transmission of said different code by said code Wheel.

4. l'n combinationgan` oiiice and a station connected by a normally closedy line circuit, a source of current for energizing saidline circuit, a re,- mote control system having a4 plurality of code transmitters including one at said office and one at said station each adapted to be, initiated only when the linev circuit is steadily energized to periodically vary the current fromsaid source in accordance with a codey a manually releasable code Wheel operablelwhen released to deliver a different impulse code to said line circuit, interference ypreventing means responsive to the release of said ccdewheelwhen a` code is being transmitted by said office or station transmitter for disconnecting said source immediately upon the releaseoi said code Wheel and until said code wheelcompletesits operation, and means associated with the transmitters of said ,remote ycontrol system forv storingr each such interrupted code for transmission When the line circuit is again steadily energized. v

5.1m a communication systemhaving a controlcnice and one or more` stations connected by a linecircuit Whichis-normally energized from a current source at said o-lice, a remote control systemhaving a plurality o codeA transmitters including one at the oice and one at `eacnstation each operable when initiated to periodically vary the` current delivered tosaid line jcircuit in accordance With a code, said remote control system having starting means for each transmitter free to; be operated at Yany time to condition such ransmitter to transmit its code but'refective to initiate-its operation only when the line circuit is steadily energized from said source and having storing means effective to maintain each actuated starting means ,in its actuated condition in the event a code is interrupted and until the corresponding code has been fully transmitted, said remote-control system also including interference preventing means effective when two or more transmitters are initiated simultaneously to prevent further operation of all but one during the resulting code, anadditional transmitter free to be operated at any time to deliver other impulse codes to said line circuit, and means controlled' by; said additional transmitter for disconnecting said source from said line circuit for the duration of each codev transmitted by said additional transmitter to preventinterference therewith Yby any remote control system transmitter.

6. Incombination with a line circuit, a, source of current for normally energizing said .line circuit, a code transmitter effective when'initiated to periodically interrupt the 'supply of current from saidsource to deliver an impulse code to said' line circuit,startng means effective only ti ony Wlienthe line circuit is steadily energized from said source for initiating its operation, meansfor stopping the operation of said transmitterin response to a prolonged deenergization of said liner circuit and for reinitiating its operation when I each transmitting contact repeatedly to control vthe current supplied from said source to thereby said line circuit is again steadily energized, an

. additional transmitter free to bek operated at any time to transmit a different impulse code to said Aline circuit, and means controlled by said additional transmitter for vdisconnecting said source from said line circuit during the transmission of said dierent impulse code. f

'7. VIn a communication system, two stations connected by line Wires, a connector relay at one station, a repeater relay attl'ie other sta-- a `code transmitter at each station, means ior at times connecting the code transmitter at one Astation to said line Wires'over front contacts of said connector relay, means for connecting the code transmitter at the other station to said line Wires over back contactsof said repeating relay,

a transmitting contact included in each code transmitter, means for operating each transmitting Contact repeatedlyrto deliver impulse` codes to said line Wires When the associated transmitter is connected thereto, means effective as long as the code transmitter at saidlone station is connected to said line Wires over front ,contacts ci said connector relay for supplying alternating current ci a `particular frequency to said line wires, and means seleotivelyresponsive to said alternating current but non-responsive to said impulse codes forenergizing said repeating relay to disconnect the other code transmitter from 8. In a ,communication system, a first and a second station connected vby line Wires, a code transmitter at each station,l a transmitting contact included in each code transmitter, means ioroperating each transmitting contact repeatedly to deliver impulse codes to said line wires when the associated co-de transmitter is connected thereto, a connectorV relay at said first stadeliver impulse codes to said line wires, a relay at said one station, selective circuitmeansr for energizing said rrelayWhen current of a distinctive character is supplied to said line Wires, means including said selective circuit means for'rendering said relay non-responsive to the current lfrom saidl source or to said impulse ccdes,vmean`s"- at anc-ther station for at times supplying current oi said distinctive character to said line Wires to energize said relay, and means controlledv by said relay when energized for disconnecting said direct current source from saidrline wires.

10. In a communication system, a plurality oi `'stationsconnected by line Wires normallyenergized iro-m a direct current source at one static-n, a code v`transmitter at each of a plurality of said stations,` a transmitting contact included in each cod transmitter, means for operating,A

each :transmitting contact repeatedly to control' the current supplied from said source to thereby deliver impulse codes to said line wires, ya relay at said one station, selectivey circuit means for energizingsaid relay when current of a distinctive character is supplied to said linewires, means including said selective circuit means vfor rendering said relay non-responsive to the current vfrom lsaid source or to said impulse codes, means at tion,l a repeating relay at the second station, se-

lectors controlled over said line Wires and selecsaid impulse codes, .means tively'responsive to elective when said connector relayis energized for connecting the codetransmitter at said first Station to said lline wires and at the same time energizing said line vWiresr by current of a distinctive character to Which said selectors are non-responsive, means responsive to said current of distinctive character in said line Wires for energizing said repeating relay, and means for disconnecting the code transmitter at said `second station from said line wires' only as'long asI said repeater relay is energized;

9,. In a communication system, static-ns connected by line wires normally energized from a direct current source atene stationy a code transmitter at each of a plurality of said stations, a transmitting contact included in each code transmitter, means for operating a plurality of another station for at times supplyingcurrent of said distinctive character to said line Wires vto energize said relay, means controlled by said relay when energized Vfor disconnecting said direct current source from said line Wires, and means at said another station for delivering other impulse codes to said line wires When-said rcurrent of distinctive character is being supplied to said line Wires. y

1l. Inlacommunicationsystem, aiirst and a second station connected by line' Wires, a code transmitter at each station, a transmitting contact included in yeach code transmittenmea'ns for operating each transmitting contact repeatedly When the associated code transmitter is connected to said line wires to thereby deliver an impulse code thereto, a repeating relay, means controlled by said repeating relay When energized to interrupt the delivery of impulse codes to said line Wires by the transmitter at said rst 'station, selective circuit means for energizing said repeating relay only When current of a distinctive character is supplied to said line wires, a vconnector relay at the second station free to be Operated at any time, means'controlled by said conl nector relay when operatedl for simultaneously connecting the code transmitter at said second station and a source of current of saidk distincy(Si) tive character to said line Wires. and storing means at said first station for storing each interrupted code for delivery in itsV entirety upon the releaseA of said repeating relay.

GEORGE W. BAUG'I-IMAN;l f l NORMAN F.l AGNEW. 

